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Modifying the landmark mapper loop to support hybrid mappings and mov…
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…e into get_vertex_index() function (#360)

Removed `get_corresponding_pointset(...)` (the function wasn't used anywhere), renamed it to `get_vertex_index(...)`, and modified/implemented the landmark mapper loop in there to support hybrid mappings, i.e. when a landmark mapping file maps some landmarks to landmark identifiers (eye.right...) and others to vertex indices. This is useful when some landmarks don't have a semantic meaning. This is used by the Blender addon (https://github.com/omar-h-omar/blender-3DMM-addon) in the Mediapipe mappings.

Also using the new `get_vertex_index(...)` in `fit_shape_and_pose(...)` now.
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omar-h-omar authored Sep 9, 2023
1 parent 330a473 commit 61ccbcb
Showing 1 changed file with 47 additions and 95 deletions.
142 changes: 47 additions & 95 deletions include/eos/fitting/fitting.hpp
Original file line number Diff line number Diff line change
Expand Up @@ -150,57 +150,51 @@ inline Eigen::VectorXf fit_shape(Eigen::Matrix<float, 3, 4> affine_camera_matrix
};

/**
* @brief Takes a LandmarkCollection of 2D landmarks and, using the landmark_mapper, finds the
* corresponding 3D vertex indices and returns them, along with the coordinates of the 3D points.
*
* The function only returns points which the landmark mapper was able to convert, and skips all
* points for which there is no mapping. Thus, the number of returned points might be smaller than
* the number of input points.
* All three output vectors have the same size and contain the points in the same order.
* \c landmarks can be an eos::core::LandmarkCollection<cv::Vec2f> or an rcr::LandmarkCollection<cv::Vec2f>.
*
* Notes:
* - Split into two functions, one which maps from 2D LMs to vtx_idx and returns a reduced vec of 2D LMs.
* And then the other one to go from vtx_idx to a vector<Vec4f>.
* - Place in a potentially more appropriate header (shape-fitting?).
* - Could move to detail namespace or forward-declare.
* - \c landmarks has to be a collection of LMs, with size(), [] and Vec2f ::coordinates.
* - Probably model_points would better be a Vector3f and not in homogeneous coordinates?
* @brief Gets the vertex index from the given landmark name using the landmark mapper and if provided the landmark definitions.
*
* @param[in] landmarks A LandmarkCollection of 2D landmarks.
* The function only returns the vertex index if the landmark mapper was able to convert the name.
*
* @param[in] landmark_name Name of the landmark, often used as identifier.
* @param[in] landmark_mapper A mapper which maps the 2D landmark identifiers to 3D model vertex indices.
* @param[in] morphable_model Model to get the 3D point coordinates from.
* @return A tuple of [image_points, model_points, vertex_indices].
* @param[in] landmark_definitions A set of landmark definitions for the model, mapping from identifiers to vertex indices.
* @return An optional int with the vertex index.
*/
template <class T>
inline auto get_corresponding_pointset(const T& landmarks, const core::LandmarkMapper& landmark_mapper,
const morphablemodel::MorphableModel& morphable_model)
inline cpp17::optional<int> get_vertex_index(const std::string landmark_name, const core::LandmarkMapper& landmark_mapper,
const cpp17::optional<std::unordered_map<std::string, int>>& landmark_definitions)
{
using Eigen::Vector2f;
using Eigen::Vector4f;
using std::vector;

// These will be the final 2D and 3D points used for the fitting:
vector<Vector4f> model_points; // the points in the 3D shape model
vector<int> vertex_indices; // their vertex indices
vector<Vector2f> image_points; // the corresponding 2D landmark points

// Sub-select all the landmarks which we have a mapping for (i.e. that are defined in the 3DMM):
for (int i = 0; i < landmarks.size(); ++i)
const auto converted_name = landmark_mapper.convert(landmark_name);
if (!converted_name)
{ // no mapping defined for the current landmark
return std::nullopt;
}
// If the MorphableModel does not contain landmark definitions, we expect the user to have given us
// direct mappings (e.g. directly from ibug identifiers to vertex ids). If the model does contain
// landmark definitions, we expect the user to use mappings from their landmark identifiers (e.g.
// ibug) to the landmark definitions. Users may also include direct mappings to create a "hybrid" mapping.
// Todo: This might be worth mentioning in the function documentation of fit_shape_and_pose.
int vertex_idx;
if (std::all_of(converted_name.value().begin(), converted_name.value().end(), ::isdigit))
{
const auto converted_name = landmark_mapper.convert(landmarks[i].name);
if (!converted_name)
{ // no mapping defined for the current landmark
continue;
vertex_idx = std::stoi(converted_name.value());
} else
{
if (landmark_definitions)
{
const auto found_vertex_idx = landmark_definitions.value().find(converted_name.value());
if (found_vertex_idx != std::end(landmark_definitions.value()))
{
vertex_idx = found_vertex_idx->second;
} else
{
return cpp17::nullopt;
}
} else
{
return cpp17::nullopt;
}
const int vertex_idx = std::stoi(converted_name.get());
const auto vertex = morphable_model.get_shape_model().get_mean_at_point(vertex_idx);
model_points.emplace_back(vertex.homogeneous());
vertex_indices.emplace_back(vertex_idx);
image_points.emplace_back(landmarks[i].coordinates);
}
return std::make_tuple(image_points, model_points, vertex_indices);
};
return vertex_idx;
}

/**
* @brief Fits the given expression model to landmarks.
Expand Down Expand Up @@ -372,34 +366,13 @@ inline std::pair<core::Mesh, fitting::RenderingParameters> fit_shape_and_pose(
// and get the corresponding model points (mean if given no initial coeffs, from the computed shape otherwise):
for (int i = 0; i < landmarks.size(); ++i)
{
const auto converted_name = landmark_mapper.convert(landmarks[i].name);
if (!converted_name)
{ // no mapping defined for the current landmark
continue;
}
// If the MorphableModel does not contain landmark definitions, we expect the user to have given us
// direct mappings (e.g. directly from ibug identifiers to vertex ids). If the model does contain
// landmark definitions, we expect the user to use mappings from their landmark identifiers (e.g.
// ibug) to the landmark definitions, and not to vertex indices.
// Todo: This might be worth mentioning in the function documentation of fit_shape_and_pose.
int vertex_idx;
if (morphable_model.get_landmark_definitions())
{
const auto found_vertex_idx =
morphable_model.get_landmark_definitions().value().find(converted_name.value());
if (found_vertex_idx != std::end(morphable_model.get_landmark_definitions().value()))
{
vertex_idx = found_vertex_idx->second;
} else
{
continue;
}
} else
const cpp17::optional<int> vertex_idx = get_vertex_index(landmarks[i].name, landmark_mapper, morphable_model.get_landmark_definitions());
if (!vertex_idx) // vertex index not defined for the current landmark
{
vertex_idx = std::stoi(converted_name.value());
continue;
}
model_points.emplace_back(current_mesh.vertices[vertex_idx].homogeneous());
vertex_indices.emplace_back(vertex_idx);
model_points.emplace_back(current_mesh.vertices[vertex_idx.value()].homogeneous());
vertex_indices.emplace_back(vertex_idx.value());
image_points.emplace_back(landmarks[i].coordinates);
}

Expand Down Expand Up @@ -857,34 +830,13 @@ inline std::pair<core::Mesh, fitting::RenderingParameters> fit_shape_and_pose(
// and get the corresponding model points (mean if given no initial coeffs, from the computed shape otherwise):
for (int i = 0; i < landmarks.size(); ++i)
{
const auto converted_name = landmark_mapper.convert(landmarks[i].name);
if (!converted_name)
{ // no mapping defined for the current landmark
continue;
}
// If the MorphableModel does not contain landmark definitions, we expect the user to have given us
// direct mappings (e.g. directly from ibug identifiers to vertex ids). If the model does contain
// landmark definitions, we expect the user to use mappings from their landmark identifiers (e.g.
// ibug) to the landmark definitions, and not to vertex indices.
// Todo: This might be worth mentioning in the function documentation of fit_shape_and_pose.
int vertex_idx;
if (morphable_model.get_landmark_definitions())
const cpp17::optional<int> vertex_idx = get_vertex_index(landmarks[i].name, landmark_mapper, morphable_model.get_landmark_definitions());
if (!vertex_idx) // vertex index not defined for the current landmark
{
const auto found_vertex_idx =
morphable_model.get_landmark_definitions().value().find(converted_name.value());
if (found_vertex_idx != std::end(morphable_model.get_landmark_definitions().value()))
{
vertex_idx = found_vertex_idx->second;
} else
{
continue;
}
} else
{
vertex_idx = std::stoi(converted_name.value());
continue;
}
// model_points.emplace_back(current_mesh.vertices[vertex_idx].homogeneous());
vertex_indices.emplace_back(vertex_idx);
vertex_indices.emplace_back(vertex_idx.value());
image_points.emplace_back(landmarks[i].coordinates);
}

Expand Down

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